MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Marshall Nordec supercharger

HI , I have a 51 TD fitted with a marshall-nordec supercharger which in turn is fitted with a 1 3/4 inch SU carb with RB needle.

The car is running rich with black and sooty plugs. I have adjusted the nut at base of carb to its upermost positionand still she is running rich !

Should I change the needle and if so to which one ?

Any advise appreciated

Jerry
j r pinna

See if you can drop the needle any farther down.
What's your air filter look like?

I installed an air/fuel ratio meter and piddled with our Marshall with an 1 1/4" SU. It was not running sooty, but I could not lean it down using the existing (and I think the leanest) needle. I dropped the needle down to the point where it blocked the mainjet at idle and would hold the slide up a touch. You know you've gone too far, then.

I really just wanted to build up the Marshall package and get it running and tested on our '50 before installing it on the '51 and then permanently install the Magnacharger onto the '50. Now I'm trying to tweak the 1 1/2" SU on the Magnacharger down, but it just hit the road yesterday (6 city driving miles total)... runs rich the idle to midrange, but still have threads to go up with on the mainjet.

Post a picture of it, I'd like to see that 1 3/4" SU.

Good luck!
Say hi to Prince Charming and Princess Cate for me.


Jim Northrup

I believe you've got far too much carburator...you should be running an 1-1/2 at the most.
Gene Gillam

I recall recently someone else was looking for an 1 3/4" SU for a Judson?

Y'now, the SU should be pretty forgiving if too large... you can tromp the gas pedal and whip the butterfly wide open, but the slide will respond to the flow and open only as far as needed.

Adjusting air/fuel ratio may be another story, though.

Show us a picture, Jerry.
Jim Northrup

Hi All , see picture below.

Jerry


j r pinna

picture again



j r pinna

Jerry,I have been running an 1 1/2" carb on my J-75 and it sometimes seems to be a little oversized for the blower. I have been considering an 1 1/4" SU just to compare the performance. I agree with Gene Gilliam.
Jim Merz TD20660 RHD

Jerry,

I also think that your carb is too big, however if you want to experiment with needles this is the best site I know of.

www.mintylamb.co.uk/suneedle/

BTW. If ever to want to get rid of your supercharger, let me know!!


John

52 TD




J Scragg

Jerry,

As I have been building and selling MG T superchargers for a number of years now, I can tell you that you might be a tad over carburated for street use. Your car will run OK with the 1-3/4" SU, but it would be smoother with say a 1-1/2". I would recomend the 1-3/4" if you are going to be driving the car hard or racing it. Try a RH (Triumph TR4)needle in your 1-3/4" SU as it is leaner and should clean up your low-speed running issues. "Fuel injection is nice, but I'd rather be blown!"

Bent T.
Benito Travato

Bent,

As I hinted above, I am interested in acquiring a supercharger for my TD. If you can help please would you contact me off line. My email is "john dot scragg at wanadoo dot fr"

John
J Scragg

Hi all

Thanks for all your comments.

I am first going to try an RF needle as advised by the person I bought the supercharger from.

If this dose not work I will take the car to a rolling road .

For all you guys thinking of getting a supercharger for a T series ... do it . The difference is amazing.

One last question for those who already have one. I have finally located a Jaeger boost guage. What is the corect pipe I should use between the guage and the supercharger to get an accurate reading ?


Cheers and thanks

Jerry
j r pinna

Jerry,
My Judson supercharger came with a hose running to the gauge.
Mort


Mort TD 1851

Jerry,

When plumbing your boost/vacuum gauge, use the smallest diameter hose or pipe you can find. I'd recomend that you use rubber hose or nylon tubing as it will not fracture like copper pipe will. Modern boost gauges often use a hard but flexable nylon tube. You can purchase a nylon tube boost/vacuum gauge plumbing kit from Autometer. www.autometer.com

Ciao, Ben T.
Benito Travato

When I had my Judson on, I used a small clear line that came with the booster gauge, worked fine.
Tom Maine (TD8105)

This thread was discussed between 01/05/2011 and 05/05/2011

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.